Discussion of reliability standards has gotten a little vague. To throw
some facts into the confusion:
I once managed to beat our Telco reps hard enough for them to provide actual
numbers. This was after a 4 hour outage on an OC-3 ring that "could self
heal in 50 milliseconds." Ameritech provided the usual mushroom treatment,
but MFS actually quoted their Operations procedure AP2402, which says:
For a DS3 facility 0-50 miles:
Availability on a 12 month period is 99.997%
Error free seconds > 99.992% over 24 hour period (7 seconds/day)
Bit error rate < 2.5*10E-11
"Performance tests shall be conducted at DS-3 level for 72 hours."
Apparently this is copied from AT&T PUB 62411. Cisco gives me the mushroom
treatment, but assuming they shoot for something like 99.992% uptime, a
simple DS3 Internet connection could have no better than 99.98% reliability.
Does anyone even come close to this number? With all of the ATM deployed
recently, I cant imagine any ISP even comes close.
Steve Norton 312-496-4601
VP Operations 312-496-4499 (fax)
InterAccess Co
steve@noc.interaccess.com